Every garden produces waste — spent plants, prunings, fallen leaves, lawn clippings. And every kitchen generates scraps — vegetable peelings, coffee grounds, eggshells. Composting turns all of it into a dark, crumbly material that feeds your soil, improves its structure, and reduces what you send to landfill. It is the simplest form of recycling, and it costs almost nothing to start.

If you have never composted before, this guide covers everything you need to know: which method fits your space, what goes in (and what stays out), and how to manage the process so you get usable compost within a few months.

Why Compost?

Composting is worth doing even if you have a small garden or only grow in containers.

Free soil improver. Finished compost replaces bagged products and is the single best amendment for garden soil. It improves drainage in clay, water retention in sand, and biological activity everywhere.
Reduced waste. Up to 30% of household waste is compostable. Diverting it from landfill reduces methane emissions — a potent greenhouse gas.
Healthier plants. Compost feeds the soil food web, not just the plants. The bacteria, fungi, and earthworms it supports make nutrients available in a slow, balanced way that synthetic fertilizers cannot match.
Less need for other fertilizers. A garden regularly amended with compost needs far fewer additional inputs. See our guide to natural fertilizing for how compost fits into a feeding programme.

What You'll Need

A composting container or a designated corner of your garden
A mix of "green" (nitrogen-rich) and "brown" (carbon-rich) materials
A garden fork or compost aerator for turning
A watering can (compost needs moisture)
Patience — the first batch takes 3-12 months depending on method

Choosing a Composting Method

The right method depends on your available space, the amount of waste you generate, and how quickly you want finished compost.

Method	Space Needed	Speed	Best For	Cost
Open heap	Large garden	6-12 months	High-volume garden waste	Free
Compost bin (plastic)	Medium garden, corner	6-9 months	Mixed garden and kitchen waste	€20-50
Wooden compost bay	Medium-large garden	6-9 months	High-volume, aesthetically neat	€40-100 (DIY)
Tumbler / rotating bin	Small garden, patio	3-6 months	Kitchen waste + small garden waste	€60-150
Wormery (vermicomposting)	Balcony, flat, indoor	2-4 months	Kitchen scraps only, small volume	€30-80
Bokashi bin	Kitchen, indoor	2 weeks (ferment) + 4 weeks (soil)	All kitchen waste including cooked food	€30-60

For most gardeners with a medium-sized garden, a plastic compost bin is the best starting point. It is affordable, widely available, and handles the typical mix of kitchen and garden waste without taking up much room. Many local councils offer subsidised bins.

Garden Planning Tip

Use Plantory's garden planner to track your compost production alongside your planting schedule. Knowing when compost will be ready helps you time soil preparation for new beds and seasonal planting.

What to Compost (and What Not to Compost)

Composting works by balancing nitrogen-rich "green" materials with carbon-rich "brown" materials. A good rule of thumb is roughly 2-3 parts brown to 1 part green by volume.

Compost This (Green — Nitrogen)

Material	Notes
Vegetable and fruit peelings	Chop large pieces for faster breakdown
Coffee grounds and tea bags	Remove staples from tea bags; compostable bags only
Fresh grass clippings	Mix with browns to avoid slimy clumps
Annual weeds (without seeds)	Avoid perennial weeds with persistent roots
Soft garden prunings	Cut into short lengths
Old cut flowers	Remove rubber bands and wire

Compost This (Brown — Carbon)

Material	Notes
Cardboard and paper	Tear into strips; avoid glossy or plastic-coated
Dry leaves	Autumn leaves are ideal; shred if possible
Straw and hay	Good structure builder
Woody prunings (shredded)	Chip or shred first; whole branches take years
Eggshells	Crush before adding; slow to break down but add calcium
Sawdust (untreated wood)	Use sparingly — very high carbon

Do NOT Compost

Cooked food, meat, fish, dairy (attracts rats; use bokashi for these)
Cat or dog faeces (pathogens)
Diseased plant material (most home composts do not reach high enough temperatures)
Perennial weed roots (bindweed, couch grass — they survive and regrow)
Treated wood, glossy paper, plastic

Step-by-Step: Setting Up Your First Compost Bin

Step 1: Choose a Location

Place your bin on bare soil in a sheltered, partially shaded spot. Contact with soil allows earthworms and microorganisms to colonise the compost. Avoid full sun (dries out too fast) or deep shade (stays too cold and wet).

Step 2: Build the Base Layer

Start with a 10-15 cm layer of coarse brown material — twigs, shredded cardboard, or straw. This creates airflow at the bottom and prevents the base from becoming waterlogged.

Step 3: Add in Layers

Alternate green and brown layers, each 5-10 cm thick. Think of it like a lasagne: a layer of kitchen scraps, then a layer of torn cardboard or dry leaves, then more scraps, and so on.

Step 4: Keep It Moist

Compost should be damp like a wrung-out sponge — not dripping wet and not bone dry. If it dries out in summer, water it. If it gets too wet in autumn, add more brown material and cover the top.

Step 5: Turn It

Every two to four weeks, use a garden fork to mix the contents. This introduces oxygen, which the composting microorganisms need. Turning speeds up the process significantly — an unturned pile can take twice as long.

Step 6: Wait and Harvest

Finished compost is dark brown, crumbly, and smells earthy — not unpleasant. Depending on your method and how often you turn it, expect to harvest usable compost in 3-12 months. In a bin, finished compost collects at the bottom while you continue adding fresh material to the top.

Troubleshooting Common Problems

Problem	Cause	Fix
Smells bad (ammonia)	Too much green, not enough air	Add brown material; turn more often
Smells rotten (anaerobic)	Too wet, compacted	Turn to aerate; add dry browns; improve drainage
Not breaking down	Too dry or too much brown	Add water; add green material; chop large pieces
Attracting flies	Exposed food scraps	Bury kitchen waste under a layer of browns
Attracting rats	Cooked food or meat in bin	Remove prohibited materials; use a bin with a solid base
Too cold (slow progress)	Small volume, winter, lack of greens	Add nitrogen-rich greens; insulate bin in winter

When and How to Use Finished Compost

Finished compost is ready when you can no longer identify the original materials — it should look and smell like rich, dark earth.

As a soil amendment: Work 5-8 cm into beds before planting. This is the best use for large batches. See our guide to improving garden soil for detailed steps.
As a mulch: Spread 3-5 cm around established plants. It feeds the soil surface and suppresses weeds. Our mulching guide covers technique and timing.
In potting mixes: Blend 1 part compost with 2-3 parts potting soil for containers. Do not use pure compost in pots — it is too dense and retains too much water.
As a lawn top-dressing: Sieve compost and spread a thin layer (1-2 cm) over the lawn in spring or autumn.

Summary

Composting is the most rewarding habit a gardener can develop. It turns waste into the best soil improver money cannot buy, reduces what goes to landfill, and creates a cycle where your garden feeds itself. Start with a simple bin, balance your greens and browns, turn it occasionally, and within a few months you will have a material that transforms everything it touches.

Every gardener should compost. If you grow anything at all, this is where it starts.

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